code: def download_det(args, overwrite=False):
      """download DET dataset and Unzip to download_dir"""
      _DOWNLOAD_URLS = [
          (
              "http://image-net.org/image/ILSVRC2015/ILSVRC2015_DET.tar.gz",
              "cbf602d89f2877fa8843392a1ffde03450a18d38",
          ),
      ]
      if not os.path.isdir(args.download_dir):
          makedirs(args.download_dir)
      for url, checksum in _DOWNLOAD_URLS:
          filename = download(
              url,
              path=args.download_dir,
              overwrite=overwrite,
              sha1_hash=checksum,
          )
          print(" dataset has already download completed")
          with tarfile.open(filename) as tar:
              tar.extractall(path=args.download_dir)
      if os.path.isdir(os.path.join(args.download_dir, "ILSVRC2015")):
          os.rename(
              os.path.join(args.download_dir, "ILSVRC2015"),
              os.path.join(args.download_dir, "ILSVRC"),
          )
  
file_path: gluon-cv/scripts/datasets/ilsvrc_det.py
imports: import argparse
  import tarfile
  import os
  import glob
  import json
  import time
  from concurrent import futures
  import numpy
  from gluoncv.utils.filesystem import try_import_cv2
  from gluoncv.utils import download, makedirs
  from gluoncv.utils.data.tracking import crop_like_SiamFC, printProgress
label_desc: Use image node_id 2 for calling a global function with example usage: download_det(args, overwrite) without return types